To reword your question:

There is a way to see a list of Lojban sentences that do NOT have English translations, but is there a way to see only a list of Lojban sentences that HAVE English translations?

Answer:

You can download such a list (go to "More"/"Downloads"), but at the moment, there is no way to see the list on the site. However, it should be possible. I imagine that we could fix this in one of two ways:

(1) Address an existing issue ticket that requests the ability to perform an "advanced query" using any combination of criteria.

(2) Add a "Directly translated into:" field to the existing "Browse by language" page. This might be a bit tricky because there's already a "Not directly translated into:" field and either there'd have to be a bit of logic to avoid contradictory settings (for example, setting both "Directly translated into:" and "Not directly translated into:" to the same language), or users would have to understand why they were getting an empty list. Also, perhaps it would slow down queries slightly, though it might well be offset by a gain in performance due to the smaller number of results we got back from the narrower queries. We should also consider reworking the "Only sentences with audio: Yes or no" drop-down to produce a three-way choice: "Audio: '---' or 'Only with audio' or 'Only without audio'. And then we're pretty close to an advanced query. In any case, I'll write up an enhancement ticket for this.